Scaling the peaks of windiness

The Beaufort scale of wind has been in use since 1805. The man after whom it was named was more than just a weather forecaster.

Yesterday, we mentioned Luke Howard (1772-1864), the man who gave the clouds their names. Continuing the theme of Great Men of Meteorological Classification, let us now introduce his contemporary, Sir Francis Beaufort (1774-1857), rear-admiral and hydrographer to the Navy.

Beaufort entered the Navy at the age of 15, and in the course of the next nine years rose to the rank of lieutenant. In a successful battle with a Spanish ship in 1800, he was wounded 19 times: "three sword cuts and sixteen musket shots" according to the Dictionary of National Biography. He was then raised to the rank of commander and given a wound pension of pounds 45.

Despite this experience, he went back to sea, where he remained until he was badly wounded in the hip in a battle with Turkish fanatics in 1812. Returning to England, he spent several years constructing charts of his maritime surveys, before being appointed hydrographer to the Navy in 1829.

In that position, he was able, at last, to disseminate an idea he had had in 1805 in connection with the measurement of wind. The Beaufort Scale, as originally devised, made no mention of wind speed (which could not be measure accurately), but only the effect of wind on the sea. It ranged from 0 - calm - sea like a mirror, up to 12 - hurricane - sea completely white with driving spray. The Beaufort numbers in between were identified by reference to waves, foam, the behaviour of wave crests and visibility. The scale remained unchanged until 1955, when the US Weather Bureau added numbers 13 to 17 to distinguish the relative severity of hurricanes.

In 1831, Commander Robert Fitzroy became one of the first to use the Beaufort Scale in his ship's log, and in 1938 it became mandatory for all ships in the Royal Navy. For the first time, log entries now had a uniform system of recording the severity of the wind.

Though he was later made a Fellow of the Royal Society, Beaufort was more a practical sailor than a meteorologist. His primary scientific interest was cartography. As the DNB notes: "He was for many years engaged in his own house in preparing the extensive Atlas published by the Society for the Diffusion of Useful Knowledge. For this labour of many years, to execute which he rose daily between five and six, he received no remuneration, except a magnificent copy of the large edition of the `Gallery of Portraits', presented only to him, the king of the French, and the Duke of Devonshire."

He did, however, have the Beaufort Sea, between Canada and Alaska, named after him.

In view of all this, it seems highly unlikely that Beaufort had much idea of what caused the winds that he so meticulously charted, so he would not have known why the United States was hit by an average of 883 tornadoes each year between 1973 and 1981.

But we don't understand that very well either. We know how a stable level of cool air sandwiched between cold winds and warm, moist air near the surface can fuel a self-propagating, twisting storm, but what makes it twist in the first place is not properly understood.

And in the field of meteorology, as in most scientific areas, "not properly understood" means we haven't the faintest idea. Francis Beaufort would happily have given it a number, then got back to his Very Useful maps.